USPTO Patents Application 09613527

(12) United States Patent

Park et ah

US006442152B1

(10) Patent No.: US 6,442,152 Bl
(45) Date of Patent: Aug. 27, 2002

(54) DEVICE AND METHOD FOR

COMMUNICATING PACKET DATA IN
MOBILE COMMUNICATION SYSTEM

(75) Inventors: Su-Won Park; Jln-Soo Park;

Soon-Young Yoon; Jae-Min Ahn;
Young-Ky Kim; Doo-Gyun Kim, all of
Seoul (KR)

(73) Assignee: Samsung Electronics, Co., Ltd. (KR)

( * ) Notice: Subject to any disclaimer, the term of this
patent is extended or adjusted under 35
U.S.C. 154(b) by 0 days.

(21) Appl. No.: 09/352,531

(22) Filed: Jul, 13, 1999

(30) Foreign Application Priority Data

Jul. 13, 1998 (KR) 98-28237

Jul. 15, 1998 (KR) 98-29180

(51) Int. CI7 H04B 7/216; H04Q 7/28;

H04Q 7/20

(52) U.S. CI 370/341; 370/320; 370/335;

370/342; 455/450

(58) Field of Searcii 370/441, 442,

370/320, 335, 350; 375/130, 132, 134,
140, 146, 147, 149

(56) References Cited

U.S. PATENT DOCUMENTS

5,673,259 A * 9/1997 Quick, Jr. 370/342

6,195,546 Bl * 2/2001 Leung et a! 455/419

6,266,331 Bl * 7/2001 Baker et al 370/335

* cited by examiner

Primary Examiner — Edward F. Urban

Assistant Examiner — Meless Zcwdu

(74) Attorney, Agent, or Firm— Oilworth & Barrese, LLP

(57) ABSTRACT

Packet data communicating device and method in a CDMA
communication system. According to a first embodiment, a
transmitting device for a base station includes a data gen-
erator for generating frame data to be transmitted, a first
mask generator for generating a long code mask for a
forward common channel, a second mask generator for
generating a long code mask for a forward common channel
to be designated as dedicated to a specific mobile station, a
selector for selecting one of the long code masks generated
in the first and second mask generators, a long code gen-
erator for generating a long code with the selected long code
mask, a scrambler for mixing the frame data received from
the data generator and the long code received from the long
code generator, and a transmitter for spreading the
scrambled frame data, for transmission.

3 Claims, 13 Drawing Sheets

944

PILOT[ALL 0]

932

r* — I
J I

I ( 1

POWER CO^frROL BfT-

CHANNEL

INTER-

ENCODER

LEAVER

/

910

/
920

7

930

WALSH

CODE

GENERATOR #0

946

WALSH CODE
GENERATOR §A

— 7 —

940

COMMON

LONG

PN CODE

CODE

GENERATOR

GENERATOR

LONG. CODE

MASK — ^
FOR CCCH p

LONG C0De/\-
-*^905

MASK
FOR USER m

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U.S. Patent Aug. 27, 2002 sheet 1 of 13

us 6,442,152 Bl

110

i_

BSC

112

BS

114

JL

MS

120

_PAGE_
F-PCH[COMMON]

ACQUISITION OF RL
PHYSICAL CHANNEL

7

126

130
140

PREAMBLE+PAGE
RESPONSE R-ACH

CHANNEL ASSIGNMENT

F-CCCH[C0MM0N]
NULL TRAFFIC

F-DCCH[DEDICATED]

PREAMBLE

ACQUISITION OF RL
PHYSICAL CHANNEL

146

150

R-DCCH/R-PICH
[DEDICATED]

BS ACK ORDER
F-DCCH[DEDICATED]
RIP INIMJZATION ^

< ^CH ASSIGNMENT PROCEDURE ^

^ USER DATA EXCHANGE ~^

/ DORMANT \
197 \ STATE /

142

160

i7rt/ CONTROL \
' \HOLD STATE/

iRn/ ACTIVE \
^^° \ STATE /

FIG, 1

(PRIOR ART)

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U.S. Patent

Aug. 27, 2002 Sheet 2 of 13 US 6,442,152 Bl

114

1-

PREAMBLE+
ORGANIZATION MESSAGE

RL

ACOUISITION OF
PHYSICAL CHANNEL

7

126

130
140

R-ACH/R-PICH

[COMMON]
CHANNEL ASSIGNMENT

F-CCCH[COMMON]
NULL TRAFFIC

F-(X:CH[DEDICATED]
PREAMBLE

ACQUISITION OF RL
PHYSICAL CHANNEL

T

146

150

R-DCCH/R-PICH
[DEDICATED]

BS ACK ORDER
F-DCCH[DEDICATED]
<^ Rtf INfTlAUZATlON N lfiO

< ^CH ASSIGNMENT PROCEDURE ^ 1 70
^ USER DATA EXCHANGE ^ 1 flO

/ DORMANT \
999 \ STATE /

142

/ CONTROL \
\HOLD STATE/

/ ACTIVE \
\ STATE /

FIQ, 2

(PRIOR ART)

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U.S. Patent Aug. 27, 2002 sheet 3 of 13 us 6,442,152 Bl

110

BSC

112

J-

BS

114

PAGE+R-CCCH

320

DESIGNATION INDICATION

F-PCH[C0MM0N]
PREAMBLE+PAGE RESPONSE

ACQUISITION OF RL

PHYSICAL CHANN

7

126

350

340

R-CCCH/R-PICH
[DESIGNATED]

PILOT ONLY

R-PICH [DESIGNATED]
CHANNEL ASSIGNMENT

F-CCCH[COMMON/OESIGNATEO]

ENABLING POWER

CONTROL &
F/R-DCCH ACTIVE

< ^ RLP INnWJZATION ^
< ^H ASSIGNMPff PROCEDURE ^
< ^ USER DATA EXCHANGE

322

/ DORMANT \
\ STATE /

332

160

^7q / CONTROL \
\HOLD STATE/

FIG. 3A

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U.S. Patent Aug. 27, 2002 sheet 4 of 13 US 6,442,152 Bl

110

J.

BSC

112

-L

114

-L

PAGE+

MS

360
140

ACQUISITION OF RL
PHYSICAL CHANNEL

CHANNEL ASSIGNMENT

F-PCH[COMMON]
NULL TRAFFIC

F-DCCH[DEDICATED]
PREAMBLE+PAGE RESPONSE

R-DCCH/R-PICH
[DEDICATED]

/ DORMANT \
\ STATE /

332

ENABLING POWER

CONTROL &
F/R-DCCH ACTIVE

<^ RLP INfTlAUZATlON
( TSCH ASSIGNMENT PROCEDURE^
USER DATA EXCHANGE ^

160

^jq/ CONTROL \
' \HOLD STATE/

180

/ ACTIVE \
\ STATE /

FIG. 3B

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U.S. Patent Aug. 27, 2002 sheet 5 of 13 US 6,442,152 Bl

110

BSC

114

360
140

PAGE+R-CCCH
ASSIGNMENT

F-PCH[C0MM0N]
NULL TRAFFIC

F-DCCH[DEDICATED]
PREAMBLE+PAGE RESPONSE

ACQUISITION OF RL
PHYSICAL CHANNEL

7

1, R-DCCH/R-PICH
[DEDICATED]

126

370

CHANNEL ASSIGNMENT

350

F-OCCH[DEDICATED]

ENABUNG POWER

CONTROL &
F/R-DCCH ACTIVE

/ DORMANT \
\ STATE /

322

< ^ RIP INfTlAUZATlON ] ^ 160
^CH ASSIGNMENT PROCEDURE ) 170 {hOU)*^SWe)
< ^ USER DATA EXCHANGE ^ 180^ ^ATE )

FIG. 3C

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U.S. Patent Aug. 27, 2002 sheet 6 of 13 US 6,442,152 Bl

110

BSC

112

-L

BS

1U

-L

MS

PREAMBLE
+ORIGINATION MESSAGE
+DESIGNATION REQUEST

ACQUISITION OF RL
PHYSICAL CHANNE L

1

126

340

R-ACH/R-PICH
[COMMON]

PILOT ONLY

R-PICH[COMMON/

DESIGNATED]
CHANNEL ASSIGNMENT

F-CCCH[COMMON/
DESIGNATED]

350

C

ENABLING POWER
CONTROL k
-DCCH ACTIVE

RLP INITIAUZATION

/ DORMANT \
420 \ STATE /

432

< ^H ASSIGNMENT PROCEDURE ^
< ^ USER DATA EXCHANGE "[ ^

160

^7q/ CONTROL \
' ^" XHOLD STATE/

isn/ ACTIVE \
^^° \ STATE /

FIG. 4

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U.S. Patent Aug. 27, 2002 sheet 7 of 13 us 6,442,152 Bl

110

BSC

112

jL

BS

530

ACQUISITION OF RL

PREAMBLE
+ORIGINATION MESSAGE
+DESIGNATION REQUEST

114

t

MS

PHYSICAL CHANN

7

E_L

126

340

560

510-^

BUFFERED DATA IS
TRANSFERRED TO
NETWORK

R-ACH/R-PICH
[COMMON]

PILOT ONLY

R-PICH[COMMON/

DESIGNATED]
CHANNEL ASSIGNMENT

F-CCCH[COMMON/

DESIGNATED]
_ POWER CONTROL

F-DCCH[DEDICATED]
DATA BURST

DATA
BUFFER h-

R-DCCH/R-PICH
[DEDICATED]

RETRANSMISSION
IS POSSIBLE J

F/R-DCCH

C

PHYSICAL CONNECTION
IS PRESERVED

420

/ DORMANT \
\ STATE /

432

580

520

RLP INmAUZATWN

:>

i ^CH ASSIGNMENT PROCEDURE^
^ USER DATA EXCHANGE

540

160
170
180

/ CONTROL \
\HOLD STATE/

/ ACTIVE \
\ STATE /

FIG. 5A

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U.S. Patent Aug. 27, 2002 sheet 8 of 13 US 6,442,152 Bl

110

J-

BSC

112

BS

530

PREAMBLE
+ORIGINATION MESSAG
+DESIGNATION REQUEST

114

M

MS

ACQUISITION OF RL
PHYSICAL CHANNEL

T

126

340

560

146

R-ACH/R-PICH
[COMMON]

CHANNEL ASSIGNMENT

F-CCCH[C0MM0N/
DEDICATED]

POWER CONTROL

F-DCCH[DEDICATED]
PREAMBLE+DATA BURST

SYNCHRONIZE TIMING
WITH REVERSE LINK

510-^

BUFFERED DATA IS
TRANSFERRED TO
NETWORK

R-DCCH/R-PICH
[DEDICATED]

DATA
BUFFER h

RETRANSMISSION
IS POSSIBLE

'f/r-dcch~

420

/ DORMANT \
\ STATE /

590

520

C

INfTlAUZATlON

>160

CONTROL \
vHOLD STATE/

dcH ASSIGNMEKT PROCEDURE^ 1 70 /,
^ USER DATA EXCHANGE ^180^ STATE )

540

FIG. 5B

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<

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U.S. Patent Aug. 27, 2002 sheet 11 of 13

US 6,442,152 Bl

eg
-co

o

00

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U.S. Patent Aug. 27, 2002

Sheet 12 of 13

US 6,442,152 Bl

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U.S. Patent Aug. 27, 2002 sheet 13 of 13 US 6,442,152 Bl

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us 6,442,

1

DEVICE AND METHOD FOR
COMMUNICATING PACKET DATA IN
MOBILE COMMUNICATION SYSTEM

CLAIM OF PRIORITY s

This application makes reference lo, incorporates the
same herein, and claims all benefits accruing under 35
U.S.C. §119 from an application entiUed DEVICE AND
METHOD FOR COMMUNICAnNG PACKET DATA IN
MOBILE COMMUNICATION SYSTEM earUer filed in the
Korean Industrial Property Office on Jul. 13, 1998, and there
duly assigned Serial No. 98-28237 and also Korean Patent
ApplicatioQ Serial No. 1998-29180.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a device and method for
communicating packet data in a mobile communication
system, and more particularly, to a device and method used 20
for rapidly assigning a dedicated channel for packet data
service in a CDMA (Code Division Multiple Access) mobile
communication system.

2. Description of the Related Art

In CDMA mobile communication systems, the IMT-2000
standard has evolved from the IS-95 standard. IS-95 sup-
ports voice service only, whereas IMT-2000 enables high-
quality voice service, transmission of moving pictures, and
internet browsing.

Data communication in the mobile communication sys-
tem is characterized by a momentary active state and a long
idle state. Accordingly, the next generation of mobile com-
munication systems assign a dedicated channel in a data
communication service only at the time when data is trans- 35
mitted. That is, dedicated traffic and control channels are
connected during data transmission and released after a
predetermined time when no data is transmitted, due to
limited radio resources, base station (BS) capacity, and
mobile power consumption. Once the dedicated channels
have been released, communication is made via common
channels, thereby increasing use efSciency of the radio
resources.

To do so, packet service is implemented in many state,
depending on channel assignment and the presence or 45
absence of state information. FIG. 6 is a state transition
diagram for packet service in a communication system.
Referring to FIG. 6, the packet service is comprised of a
packet null state, an initialization state, an active state, a
control hold state, a suspended state, a dormant state, and a 50
reconnect state. Packet service options are connected in the
control hold state, active state, and suspended state.

Upon request for packet service in the packet null state,
the initialization state is entered where a connection attempt
for packet service is performed, and transition to the control 55
hold state occurs if a dedicated control channel is estab-
lished. The dedicated control channel is needed to transmit
a layer 3 (L3) message and a medium access control (MAC)
message. Then, upon entering the active state, forward and
reverse dedicated control channels and traffic channels are 60
maintained with RLP (Radio Link Protocol) frames being
communicated on these channels. If a relatively short inac-
tive time period is set, the suspended state is entered to
efficienUy use radio resources and conserve mobile station
(MS) power. In the suspended state, the dedicated control 65
and traffic channels are released but can be re -assigned in a
relatively short time because both the BS and the MS retain

152 Bl

2

stams information including RLP initialization, traffic chan-
nel assignment, and encryption variables. If there is no data
exchanged for a predetermined time, the suspended state
transitions to the dormant state. In the dormant state, only a
PPP (Point- to-Point Protocol) connection is maintained and
if transmit data is generated, a reconnect state is entered. If
the dedicated control channel is established, the reconnect
state transitions to the control hold state. While the MS and
the BS are in a common channel state, such as the
suspended, dormant, and reconnect states, the MS monitors
a paging channel and a common control channel on a
forward fink, and the BS monitors an access channel and a
common control channel on a reverse link. There may be a
plurality of paging channels and access channels. Each
paging channel is distinguished by a different Walsh code
and each access channel is distinguished by a different long
code.

In FIG. 6, after the active state transitions to the sus-
pended state through the control hold state in the absence of
data for a predetermined time during a data communication,
messages are exchanged on common channels. Upon gen-
eration of a control message for resuming data transmission,
the BS attempts to connect to the MS on a paging channel
and then the MS transmits a response message on an access
chanael. However, this common channel message transmis-
sion is susceptible to message contention if other MSs use
the same access channel, resulting in a reception failure in
the BS. If each MS fails to receive an acknowledgement
from the BS within a predetermined time, it perceives the
occurrence of message contention and resumes a message
transmission after a randomized time delay. If repeated
attempts to access the access channel for predetermined
times fail, the procedure starts again. Information is trans-
mitted on the access channel in access channel slots.

In the mechanism of transmitting an access channel
message, the entire process of sending one message and
receiving (or failing to receive) an acknowledgement for that
message is called an access attempt. Each transmission in
the access attempt is called an access probe. Each access
probe consists of an access channel preamble and an access
channel message capsule. When a message contention
occurs, an access probe is re -transmitted with a power level
set at a specified amount higher than the previous access
probe's power level after a randomized lime delay.

In the case of the MSs initiation of data communication,
the same message transmission procedure is performed
without the paging step of the BS. If an access channel
message is too long to be sent at one time, it is divided into
appropriate segments prior to transmission and the above
procedure for each segment.

After exchanging the common channel messages, the BS
assigns a dedicated code channel and sends a traffic channel
assignment message on the dedicated channel. When the BS
responds to the message, user data is sent on a dedicated
traffic channel.

The procedure of assigning the dedicated channel is
implemented in the same manner during transitions from the
suspended state to the active state and from the dormant state
to the active state. Transition from the suspended slate to the
active state requires service option negotiation associated
with radio resources assignment and RLP initialization
because only PPP information is reserved and no radio
resources-related information exists in the dormant state.

FIG. 1 describes a conventional data service resuming
procedtire for a call initiated by a BS in a dormant state. A
BS 112 sends a forward control message for resuming a data

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3

service to a corresponding addressed MS 114 on a paging
channel (F-PCH) being a forward common channel (step
120). Then, the MS 114 sends a response message for the
control message on a reverse access channel (R-ACH) (step
122). On the reverse access channel, a preamble precedes an
access channel message to facilitate acquisition of a reverse
physical channel in the BS 112 (step 126).

The entire process of sending one message and receiving
(or failing to receive) an acknowledgement for that message
is called an access attempt. Each transmission in the access
attempt is called an access probe. Each access probe is
comprised of a preamble and a message capsule. Upon
contention of access probes, the mobile station transmits an
access probe at a progressively higher power level than the
previous access probe after a randomized delay. Here,
transmission of the preamble is transmitted on a reverse pilot
channel to synchronize timing between the BS and the MS
which had a communication interrupted.

Reverse access channels share a long code. In a long code
sharing scheme, an MS uses a Hash function to determine a
long code among all available long codes (access channel
long codes) in its initialization state, so that all MSs fairly
share the long codes for access channels. A reverse pilot
channel for channel estimation is spread by the long code of
a reverse access channel and transmitted in parallel with the
reverse access channel only for a time period when the
reverse channel message exists. The two channels are dis-
tinguished by different orthogonal codes.

The preamble is transmitted on the reverse pilot channel
at a higher transmit power level than the pilot channel,
accompanied by a reverse access channel message. That is,
the preamble is a segment of the pilot channel, with a
relatively high transmit power.

If the BS 112 succeeds in synchronization with a reverse
link and receiving the access channel message (step 126), it
sends a dedicated channel assignment message on a forward
common control channel (F-CCCH) (step 130) and null
traffic on a forward dedicated control channel (F-DCCH)
(step 140). If the MS 114 confirms that the dedicated channel
is properly assigned from an analysis of the null frame of the
F-DCCH, it sends a preamble on its \mique code channel
(R-PICH) (step 142). The preamble is used to recover
synchronization between the BS 112 and the MS 114 which
have experienced a temporary call interruption, during the
channel assignment.

Then, the BS 112 sends an acknowledgement on the
F-DCCH and the MS 114 stops transmitting the preamble
(step 150). Thus, the MS 114 is capable of sending a
message on a dedicated channel. RUP is initialized for
packet data service and service options are connected (step
160). Hence, the control hold state is entered, and if a
supplemental channel is successfully assigned (step 170),
the active state is entered where packet data is communi-
cated (step 180).

Meanwhile, if the BS 112 initiates a call in the suspended
state, the data service can be resumed without step 160 in the
above procedure.

FIG. 2 depicts a conventional data service resuming
procedure for an MS initiated call in a dormant state. This is
the same as the procedure described in FIG. 1 except that the
MS 114 sends a packet service origination message on an
access channel (step 222). Upon reception of the message by
the BS 112, the subsequent steps are performed as shown in
FIG. 1.

In resuming a data service for an MS initiated call in a
suspended state, step 160 can be omitted in the above
procedure.

12,152 Bl

4

A conventional data service resuming procedure which
exchanges messages on common channels as illustrated in
FIGS, 1 and 2, has many disadvantages.

There is a limitation inherent in long code sharing. The
5 equal assignment of available long codes for common
channels to mobile stations makes it impossible to control an
individual probability of access channel contention for each
mobile station. In view of frequent state transitions in the
packet data service, the time required for the preliminary
10 process for data transmission including channel acquisition
is longer than an actual data transmission time.

Additionally, in a communication on a common channel,
the MS must send a message in a slot allocated to the MS,
thereby incurring a transmission delay while awaiting the
allocated slot.

Also, since a reverse pilot channel is activated only at the
time when an access channel message or a reverse common
channel message is transmitted, the BS should reacquire the
PN sequence of the MS prior to transmission of a channel
assignment message. Accordingly, the MS repeatedly per-
forms an access attempt in which a preamble is sent at a
relatively high transmit power level, followed by an access
channel message. Therefore, power is excessively consumed
and the BS reacquisition step is added.

Finally, data can be transmitted only through a regular
state transition. In other words, if the amount of data to be
transmitted at a time is small, the resources that a prelimi-
nary process for resuming data transmission takes is larger
than that of actual data transmission, leading to inefficient
use of resources.

In a conventional designation of a common channel, an
MS transmits a message on a reverse access channel and
receives a response for the message on a forward paging
channel. Thus, there may exist a plurality of forward paging
channels and reverse access channels. Each forward chaimcl
is distinguished by a different Walsh code and each reverse
channel by a different long code in a CDMA mobile com-
munication system.

Upon generation of a message to be transmitted, the MS
sends the message together with a preamble to the BS on an
available access channel at an appropriate power level, and
awaits an acknowledgement from the BS. If a different MS
selects the same access channel, message contention occurs.
45 Then, the BS may fail to receive the MS initiated message
for a predetermined time. If it does, the MS sends the same
message again using a power level set at a specified amount
higher than the previous message and awaits an acknowl-
edgement.

50 In the conventional mechanism of sending access chan-
nels being reverse common channels, concurrent message
transmissions from MSs with the same long code are likely
to caxise message contention, leading to message losses. This
is called contention-based random access.

55 When message contention occurs, the MS perceives the
message contention in a predetermined time and resumes a
message transmission after a randomized time delay. The
MS performs an initial attempt to access the BS at a
predetermined power level. When it fails to receive an

60 acknowledgement from the BS, it performs the next attempt
using a power level set at a specified amount higher than the
previous attempt. If repeated attempts to access the access
channel for predetermined times fail, the procedure starts
again. Information is transmitted on the access channel in

65 access channel slots and access channel frames.

For an MS to transmit a message which is too long to be
transmitted at one time, the message must be divided into

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5 6

appropriate segments which are sent a plurality of times. FIG. 8 is a block diagram of a receiver in an MS,

When other MSs attempt to transmit messages using the corresponding to the transmitter of FIG. 7;

same long code, message contention occurs. In this case, a FIG. 9 is a block diagram of a transmitter in an MS

long delay is involved in transmitting the entire message od according to the present invention; and

the access channel. S pj^ ^ ^ block diagram of a receiver in a BS,

The message contention can be prevented by designating corresponding to the transmitter of FIG. 9.
a channel assigned by a BS as dedicated to an MS for

transmission of a common channel message. On the other DETAILED DESCRIPTION OF THE

hand, to designate a forward common channel as dedicated, PREFERRED EMBODIMENTS

the MS requests for channel continuously transmit a com- lO ^ ^^^^ Station Controller) in the present invention

mon channel message, and then the BS sends a response is a controller disposed between a BS and an exchange or

message which includes the ID of an available channel. between a BS and an IWF (Inter-Working Function), for

The present invention provides a method of transitioning performing location registration of an MS, service

from a dedicated channel released state to a data transmis- connection, call management, and BS control,

sion state by rapidly assigning a dedicated channel. [STote that like reference numerals denote the same com-

SUMMARY OF THE INVENTION ponents or the same steps in the drawings, and a description

of the present invention will be given, focussing on the
An object of the present invention is to provide device and difference between the prior art and the present invention,
method for communicating packet data, in which data trans- ^Vhile the embodiments herein apply the present invention
mission on a common channel is minimized and a data ^0 ^ CDMA mobile communication system, the present
transmission state using a dedicated channel, or a channel invention is not limited to CDMA systems only,
designated as dedicated, is rapidly entered in order to ^ ^ ^j^^^ ^.^ ^ transmitting device
efficienUy use resources and support rapid data service. according to an embodiment of the present invention. Refer-
According to one aspect of the present mvention, the ^lug pj^ 7^ ^ channel encoder 710 encodes data to
above object can be achieved by providing a BS transmitting transmit in a communication channel. An interleaver 720
device in a mobile communication system. In the transmit- randomizes encoded symbols for burst errors in the output of
ting device, a data generator generates frame data to be channel encoder 710. A selector 705 selects a different
transmitted, a first mask generator generates a long code long code mask according to a forward common channel and
generator for a forward common channel, a second mask a forward dedicated channel. It selects a long code mask for
generator generates a long code mask for a forward common ^ specific MS when a forward common channel is desig-
channel to be designated as dedicated to a specific mobile ^ated as dedicated upon request for the designation by the
station, a selector selects one of the long code masks -j^^ j^Qg j^^y ^ ^ specific long code mask
generated in the first and second mask generators, a long designate a common channel as dedicated or a long
code generator generates a long code by use of the selected ^ode generated using an ESN (Electronic Serial Number) of
long code mask, a scrambler mixes the frame data received the MS. A long code generator 712 generates a long code
from the data generator and the long code received from the ^^th the selected long code mask, A decimator 722 takes one
long code generator, and a transmitter spreads the scrambled fj.^^ ^^^^ predetermined chip of the long code to match
frame, for transmission. a symbol rate at the output of the interleaver 720. A mixer
BRIEF DESCRIPTION OF THE DRAWINGS 40 muUiplies the outputs of the interleaver 720 and the

_ . . decimator 722, for scrambling transmit information to allow

The above objects and advantages of the present invention . ^ ^^^-^^^ • ^^^^ ^^^^ ^^^^ ^ ^^^-^^

will become more apparent by describmg in detail preferred information

embodiments thereof with reference to the attached draw- . , . * /h^ttvx -ia 1 * * r *u

in s in which' multiplexer (MUX) 730 multiplexes the output or the
ings m w ic . .45 mixer 724 and a power control bit sent to control the

HG. 1 is a flowchart depicting a conventional data service ^^^^^-^ ^^^^ ^„ j^g. The mulUplexing can be imple-

resuming procedure between a BS and an MS m a dormant ^^^^^^ ^.^^ ^^-^-^^ multiplexing, and punc

state for call mitiation by the BS; ' ^^^^^ p^^^^ ^^^^^y insertion. The insertion location

FIG. 2 is a flowchart depicting a conventional data service power control bit may be preset by a mobile com-

resuming procedure between a BS and a MS in a doraiant munication system or randomly determined,

state for call initiation by the MS; ^ y^^^^ generator 740 is a type of orthogonal

HGS. 3A, 3B, and 3C are flowcharts depicting embodi- ^.q^^ generator for orthogonal channelization among for-

ments of data service resuming procedures between a BS ^^rd channels and generates a Walsh code symbol #A of a

and an MS in a dormant state for call initiation by the BS ^^Ish code set. A mixer 742 multiplies the outputs of the

according to embodiments of the present invention; multiplexer 730 and the Walsh code #A generator 740, for

FIG. 4 is a flowchart depicting an embodiment of a data orthogonal modulation. A Walsh code #0 generator 744

service resuming procedure between a BS and an MS in a generates a Walsh code symbol #0 for a pilot channel in the

dormant state in the case of a call initiation by the MS Walsh code set. A mixer 746 multiplies the output of the

according to a fourth embodiment of the present invention; Walsh code #0 generator 744 by a predetermined value (+1

FIGS. 5A and 5B are flowcharts depicting other embodi- in the present invention) to produce a forward pilot channel

ments of the data service resuming procedure between a BS for a receiver to use for channel estimation,

and an MS in a dormant state for caU initiation by the MS An adder 750 adds the outputs of the mixers 742 and 746.

according to a fifth embodiment of the present invention; A common PN code generator 760 generates a PN sequence

FIG. 6 is a state transition diagram for packet data service assigned to a cell to identify the cefl. A dedicated PN code
in accordance viath the prior art; 65 generator 762 for an MS "#m" generates a PN sequence for

FIG. 7 is a block diagram of a transmitter in a BS PN spreading a forward common channel to be designated

according to the present invention; as dedicated. As described above, the forward common

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channel can also be designated as dedicated with a speciflc
long code mask. The dedicated PN code generator 762 can
be separately procured or replaced by the long code gen-
erator 712 to implement the same function. A selector 764
selectively switches the outputs of the common PN code
generator 760 and the dedicated PN code generator 762. A
mixer 766 multiphes the sum of the forward channels
received from the adder 750 by the selected PN sequence,
for PN spreading. The output of the mixer 766 is transmitted
through a low pass filter (LPF) 770, an RF (Radio
Frequency) transmitting end 772, and a transmission
antenna.

FIG. 8 is a block diagram of an MS receiver correspond-
ing to the BS transmitter shown in FIG. 7. Referring to FIG.
8, a mixer 866 receives a signal through a reception antenna,
an RF receiving end 872, and an LPF 870. The selector 764
selects the same PN sequence used in the BS transmitter
between the outputs of the common PN code generator 760
and the dedicated PN code generator 762. The mixer 866
multiplies the selected PN sequence by the output of the LPF
870.

A mixer 846 multiplies the output of the mixer 866 by the
output of the Walsh code #0 generator 744 in order to extract
the pilot channel for channel estimation. A channel estimator
850 estimates a channel with the extracted pilot channel, A
complex conjugator 852 produces the complex conjugate of
the channel's estimated value. A mixer 842 multiplies the
output of the mixer 866 by the Walsh code symbol #A used
in the BS, thereby extracting the information transmitted to
the MS. A mixer 826 multiplies the complex conjugate by
the output of the mixer 842, for coherent demodulation. A
demultiplexer (DEMUX) 830 demultiplexes the coherent
demodulation signal iiito the power control bit and the data
received from the BS.

The selector 705 selects the same long code mask that was
Tised in the BS transmitter. The long code generator 712
generates a long code utilizing the selected long code mask.
The decimator 722 takes one chip from each predetermined
chip of the long code to match a symbol rate at the output
of the demultiplexer 830. A mixer 824 multiplies the data
separated by the demultiplexer 830 by the output of the
decimator 722, for descrambling. A deinterleaver 820
deinterleaves the output of the mixer 824. A channel decoder
810 channel-decodes the deinterleaved signal,

FIG. 9 is a block diagram of an MS transmitter according
to another embodiment of the present invention. Referring to
FIG. 9, a channel encoder 910 detects and recovers errors in
a communication channel. An interleaver 920 randomizes
burst errors in the output of the channel encoder 910. A
multiplexer 930 multiplexes the output of the interleaver 920
and a power control bit which is sent to control the transmit
power of a BS. The multiplexing can be implemented in two
ways: time division multiplexing, and puncturing and power
control bit insertion. The insertion location of the power
control bit may be preset by a mobile communication system
or randomly determined.

A Walsh code #a generator 940 is a type of orthogonal
code generator for orthogonal channelization among reverse
channels and generates a Walsh code symbol #a of a Walsh
code set. A mixer 942 multiplies the outputs of the multi-
plexer 930 and the Walsh code #a generator 940, for
orthogonal modulation. A Walsh code #0 generator 944
generates a Walsh code symbol #0 for a pilot channel in the
Walsh code set. A mixer 946 multiplies the output of the
Walsh code #0 generator 944 by a predetermined value (+1
in the present invention) to thereby produce a reverse pilot

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channel for a receiver to use for channel estimation. A
second multiplexer 932 may be used to multiplex the power
control bit on the pilot channel. In this case, the multiplexer
930 is omitted and the output of the interleaver 920 is

5 directly applied to the input of the mixer 942. An adder 950
adds the outputs of the mixers 942 and 946. A common PN
code generator 960 generates a PN sequence assigned to a
cell to identify the cell,

A selector 905 selects a different long code mask accord-
ing to a reverse common channel and a reverse dedicated
channel. A long code generator 912 generates a long code
with the selected long code mask. A mixer 914 generates a
spreading sequence used to spread the output of the mixer
966 by multiplying the outputs of the common PN code

j5 generator 960 and the long code generator 912. The output
of the mixer 966 is transmitted through an LPF 970, an RF
transmitting end 972, and a transmission antenna.

FIG, 10 is a block diagram of a BS receiver corresponding
to the MS transmitter of FIG. 9. Referring to FIG. 10, a

20 mixer 1066 receives a signal through a reception antenna, an
RF receiving end 1072, and an LPF 1070. The selector 905
selects the same long code mask used in the transmitter. The
long code generator 912 generates a long code utilizing the
selected long code mask. The mixer 914 generates a

25 sequence for desp reading the output of the mixer 1066 by
multiplying the outputs of the common PN code generator
960 and the long code generator 912.

A mixer 1046 multiphes the output of the mixer 1066 by
the output of the Walsh code #0 generator 944 in order to

30 extract the pilot channel for channel estimation. A demulti-
plexer 1032 is used when a power control bit is received on
the pilot channel in which case a demultiplexer 1030 is not
used. A channel estimator 1050 estimates a channel with the
extracted pilot channel. A complex conjugator 1052 pro-

35 duces the complex conjugate of the channel estimated value.
A mixer 1042 multiplies the output of the mixer 1066 by the
Walsh code symbol #a used in the MS, thereby extracting the
information transmitted to the BS. A mixer 1026 multiplies
the complex conjugate by the output of the mixer 1042, for

40 coherent demodulation. The demultiplexer 1030 demulti-
plexes the coherent demodulation signal into the power
control bit and the data received from the MS. When the
power control bit is loaded on the reverse pilot channel, the
demultiplexer 1030 is omitted and the output of the mixer

45 1026 is directly apphed to the input of a deinterleaver 1020.
The deinterleaver 1020 deinterleaves the data received from
the demultiplexer 1030 and a channel decoder 1010 channel-
decodes the deinterleaved signal.

Referring now to FIG. 3 A, FIG. 3 A is a flowchart illus-

50 trating signal flow between a BS and an MS in an embodi-
ment of a data service resuming procedure when a BS
initiates a call in a dormant state according to the present
invention. The BS 112 sends the MS 114 a forward control
message including information about designation of an

55 R-CCCH as dedicated on an F-PCH which is a forward
common channel (step 320). The MS 114 sends the BS 112
a response message on an R-CCCH designated as dedicated
based on the forward control message (step 322). The
response message may include information about designa-

60 tion of an F-CCCH as dedicated. Then, the BS 112 synchro-
nizes its timing with the reverse link via the R-CCCH
designated as dedicated (step 126). An R-PICH for channel
estimation is maintained even if no common control channel
message (step 332) exists. This obviates the need for sending

65 a preamble by the MS to aUow the BS to reacquire a PN
sequence used for PN spreading in the MS. The BS 112
sends the MS 114 a channel assignment message on an

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F-CCCH (step 340), The F-CCCH can be designated as null trafiBc, and BS reacquisition which are caused by

dedicated upon request from the MS 114 in one of two message communicatioo on CCCHs can be overcome,

methods as described below. Therefore, the F-DCCH and the R-DCCH are activated in a

Where there is loss of orthogonality on a forward link and short time relative to the prior art, thereby enabling a rapid
no transmission delay of a channel assignment message. In 5 data transmission. The subsequent procedure (steps 160,

this method, an F-CCCH can be spread by a particular PN 170, and 180) is performed in the same manner as FIG. 1.

sequence generated by the dedicated PN code generator 762 In resuming a data service for a call initiated by a BS in

of FIG. 7. In such a case forward channel orthogonality is a suspended state, step 160 can be omitted in the above

lost only during channel assignment message transmission. procedure.

Therefore, the BS 112 notifies the MS 114 of an orthogonal lO ^iq g flowchart depicting a further embodiment of

code to be used by the channel assignment message (step the data service resuming procedure for a call initiated by a

340). Then, the selector 764 of FIGS. 7 and 8 selects the BS in a dormant state. Referring to FIG. 3C, the BS 112

common PN code generator 760 in the BS 112 and the MS sends the MS 114 a forward control message for resuming

114 and the Walsh code #A generator 740 is set depending a data service on an F-PCH which is a forward common
on the assigned orthogonal code. 15 ^^^^^^i (step 360). The forward control message includes

Where there is no loss of forward channel orthogonality, information about assignment of bidirectional dedicated

a message is sent to the MS 114 only in a slot assigned to the channels. The BS 112 sends null traffic on the assigned

MS since an F-CCCH is used in time division. Thus, the F-DCCH (step 140). The MS 114, which has received the

channel assignment message cannot be directly sent to the forward control message and the channel assignment

MS 114 when it is generated. The selector 705 of FIG. 7 message, analyzes the null traffic (step 322). Then, the MS

selects a long code mask unique to the MS 114 and the mixer 114 sends the BS 112 a response message on the assigned

724 scrambles data with a long code generated by the long R-DCCH. Prior to transmission of the response message, the

code mask, so that an MS which does not tisc the long code MS 114 sends a preamble for a predetermined time period at

mask detects errors in a CRC (Cyclic Redundancy Code) a power level required to facilitate synchronization acqui-
check following channel decoding. The BS 112 notifies the ^ sition in the BS 112, and then the response message is sent

MS 114 of an orthogonal code to be used by the channel on an R-DCCH in parallel with a reverse dedicated pilot

assignment message (step 340). Then, the selector 705 of channel. The BS 112 synchronizes its timing with the

FIGS. 7 and 8 in the BS 112 and the MS 114 selects a long reverse hnk via the R-DCCH (step 126). The BS 112 can

code mask unique to the MS 114 and the Walsh code #A proceed to a channel reassignment on the F-DCCH (step

generator 740 is set depending on the assigned orthogonal 370).

code. Since the assignment of bidirectional DCCHs enables a
Since the assignment of bidirectional DCCHs enables a power control (step 350), the conventional problem of
power control (step 350), the conventional problem of excessive power consumption, unnecessary transmission of
excessive power consumption, tmnecessary transmission of a preamble and nuU traffic, and BS reacquisition which are
a preamble and null traffic, and BS reacquisition which are caused by message communication on CCCHs can be over-
caused by message communication on CCCHs can be over- come. Therefore, the F-DCCH and the R-DCCH are acti-
come. Therefore, an F-DCCH and an R-DCCH are activated vated in less time when compared to the prior art, thereby
in a short time relative to the prior art, thereby enabling a enabling a rapid data transmission. The subsequent proce-
rapid data transmission. The subsequent procedure (steps dure (steps 160, 170, and 180) is performed in the same
160, 170, and 180) is performed in the same manner as FIG. manner as FIG. 1.

1. In resuming a data service for a call initiated by a BS in

In resuming a data service for a call initiated by a BS in a suspended state, step 160 can be omitted in the above

a suspended state, step 160 can be omitted in the above procedure.

procedure. 45 FIG. 4 is a flowchart depicting an embodiment of a data

FTG. 3B is a flowchart depicting another embodiment of service resuming operation for a call initiated by an MS in

the data service resuming procedure for a call initiated by a a dormant state. Referring to FIG. 4, the MS 114 sends a

BS in a dormant state. Referring to HG. 3B, the BS 112 reverse control message to the BS 112 for resuming a data

sends the MS 114 a forward control message for resuming service on an R-ACH (step 420). The control message may
a data service on an F-PCH which is a forwarf common 50 include information about designation of an F-CCCH as

channel (step 360). The forward control message includes dedicated. Then, the BS 112 synchronizes its timing with the

information about assignment of bidirectional dedicated reverse link via the R-ACH (step 126). An R-PICH for

channels. The BS 112 sends null traffic on the assigned channel estimation is maintained even if there exists no

F-DCCH (step 140). The MS 114, which has received the common control channel message (step 432). This obviates
forward control message and the channel assignment 55 Ihc need for the subsequent step of sending a preamble by

message, analyzes the nuD traffic (step 322). Then, the MS ihe MS to allow the BS to reacquire a PN sequence used for

114 sends the BS 112 a response message on the assigned PN spreading in the MS. The R-PICH is spread by a PN

R-DCCH. Prior to transmission of the response message, the sequence for the R-CCCH for a predetermined time and then

MS 114 sends a preamble for a predetermined time period at by a PN sequence for an R-DCCH. The BS 112 sends the
a power level required to facilitate synchronization acqui- 60 MS 114 a channel assignment message on an F-CCCH (step

sition in the BS 112, and then the response message is sent 340). The F-CCCH can be designated as dedicated upon

on the R-DCCH in parallel with a reverse dedicated pilot request from the MS 114.

channel. The BS 112 synchronizes its timing with the Since the assignment of bidirectional DCCHs enables a

reverse link via the R-DCCH (step 126). Since the assign- power control (step 350), the conventional disadvantages of
ment of bidirectional DCCHs enables a power control (step 65 excessive power consumption, unnecessary transmission of

350), the conventional problem of excessive power a preamble and null traffic, and BS reacqiiisition which are

consumption, unnecessary transmission of a preamble and caused by message communication on CCCHs can be over-

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12

10

20

come. Therefore, an F-DCCH and an R-DCCH are activated
in less time when compared to the prior art, thereby enabling
a rapid data transmission. The subsequent procedure (steps
160, 170, and 180) is performed in the same manner as FIG,
2. 5

In resuming a data service for a call initiated by an MS in
a suspended state, step 160 can be omitted in the above
procedure.

FIG. 5 A is a flowchart depicting another embodiment of
the data service resuming procedure for a call initiated by an
MS in a dormant state, in which burst data generated by the
MS is sent on an R-DCCH, that is, data is sent in the dormant
state without entering a data transmission slate by assigning
a dedicated traffic channel. Referring to FIG. 5 A, the MS 114
sends the BS 112 a reverse control message for resuming a
data service on an R-CCCH (step 420). The control message
may include information about designation of an F-CCCH
as dedicated. Then, the BS 112 synchronizes its timing with
the reverse link via the R-CCCH (step 126). An R-PICH for
channel estimation is maintained even if there exists no
common control channel message (step 432). This obviates
the need for the subsequent step of sending a preamble by
the MS to allow the BS to reacquire a PN sequence used for
FN spreading in the MS. The R-PICH is spread by a PN
sequence for the R-CCCH for a predetermined time and then
by a PN sequence for an R-DCCH. The BS 112 sends the
MS 114 a channel assignment message on an F-CCCH (step
340). The F-CCCH can be designated as dedicated upon
request from the MS 114 in step 420. The BS 112 performs
a power control for the reverse link via an F-DCCH assigned
in step 340 (step 560). Then, the MS 114 sends the BS 112
data bursts on an R-DCCH (step 580). The data is stored in
a buffer of the BS 112 (step 510). Frames having errors
during the transmission are recovered through retransmis-
sion (step 520). The buffered data is transmitted to a network
through a BSC 110 (step 530). If the amount of the received
data exceeds the capacity of the buffer, the assigned DCCHs
are maintained (step 540). The subsequent procedure (steps
160, 170, and 180) is performed in the same manner as FIG.

In resuming a data service for a call initiated by an MS in
a suspended state, step 160 can be omitted in the above
procedure.

FIG. 5B is a flowchart depicting a further embodiment of 45
the data service resuming procedure for a call initiated by an
MS in a dormant state, in which burst data generated by the
MS is sent on an R-DCCH, that is, data is sent in the dormant
state without entering a data transmission state by assigning
a dedicated traffic channel. Referring to FIG. 5B, the MS 114 50
sends the BS 112 a reverse control message for resuming a
data service on an R-CCCH (step 420). The control message
may include information about designation of an F-CCCH
as dedicated. Prior to transmission of the reverse control
message, the MS 114 sends a preamble for a predetermined 55
time period at a power level required to facilitate synchro-
nization acquisition in the BS 112, and then the control
message is sent on the R-CCCH in parallel with a reverse
pilot channel. Then, the BS 112 synchronizes its timing with
the reverse link via the R-CCCH (step 126). When no
R-CCCH message exists, the reverse pilot channel is no
longer sent after a predetermined time.

The BS 112 sends the MS 114 a channel assignment
message on an F-CCCH (step 340). The F-CCCH can be
designated as dedicated upon request from the MS 114 in 65
step 420. The BS 112 performs a power control for the
reverse link via an F-DCCH assigned in step 340 (step 560).

Then, the MS 114 sends the BS 112 data bursts on an
R-DCCH (step 590). More particularly, the MS 114 sends a
preamble for a predetermined time period at a power level
required to facilitate synchronization acquisition in the BS
112, and then the data bursts are sent on the R-DCCH in
parallel with a reverse pilot channel. Then, the BS 112
synchronizes its timing with the reverse link via the
R-DCCH (step 146). The data is stored in a buffer of the BS
112 (step 510). Frames having errors during the transmission
are recovered through retransmission (step 520). The buff-
ered data is transmitted to a network through a BSC 110
(step 530). \f the amount of the received data exceeds the
capacity of the buffer, the assigned DCCHs are maintained
(step 540). The subsequent procedure (steps 160, 170, and
180) is performed in the same manner as FIG. 2.

In resuming a data service for a call initiated by an MS in
a suspended state, step 160 can be omitted in the above
procedure.

As described above, the present invention is advantageous
in that resources are efficiently used and a rapid data service
is supported because data transmission on a common chan-
nel is minimized and a data transmission state using a
dedicated channel or a channel designated as dedicated is
rapidly entered.

While the present invention has been described in detail
with reference to the specific embodiments, they are mere
exemplary applications. Thus, it is to be clearly understood
that many variations can be made by anyone skilled in the
art within the scope and spirit of the present invention.

What is claimed is:

1. A transmitting device for a base station in a mobile
communication system, comprising:

a common channel data generator for generating a com-
mon channel data frame to be transmitted;

a first mask for generating a first long code for a forward
conimon channel;

a second mask for generating a second long code for a
forward common channel to be designated as dedicated
to a specific mobile station;

a selector for selecting one of the first and second long
code masks generated in the first and second mask;

a long code generator for generating a long code with the
selected long code mask from the selector;

a mixer for mixing the frame data received from the data
generator and the long code received from the long
code generator, and

a transmitter for spreading a mixer output for transmis-
sion.

2. A transmitting device for a mobile station in a mobile
communication system, comprising:

an orthogonal modulator for orthogonally modulating

frame data to be transmitted;
a first mask for generating a first long code for a reverse

common channel;
a second mask for generating a second long code for a

reverse common channel to be designated as dedicated;
a selector for selecting one of the first and second long

code masks in the first and second mask;
a long code generator for generating a long code with the

selected long code mask;
a mixer for producing a spreading code by mixing a

common PN code with the generated long code;
a spreader for multiplying the orthogonally modulated

frame data by the spreading code; and

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a transmitter for upconverting the frequency of the output

of the spreader, for transmission.
3. The transmitting device of claim 2, further comprising:
a pilot channel transmitter for spreading a reverse pilot
channel signal to be transmitted simultaneously with
the common channel message by the spreading code

14

and continuously transmitting the spread reverse pilot
channel signal; and
wherein said reverse common channel is designated upon
a call origination in a dedicated channel released state.

09/05/2003, EAST version: 1.04.0000

UNITED STATES PATENT AND TRADEMARK OFFICE

CERTIFICATE OF CORRECTION

PATENT NO.
DATED

: 6,442,152 Bl
: August 27, 2002

Page 1 of 1

INVENTOR(S) : Su- Won Park etal.

It is certified that error appears in the above-identified patent and that said Letters Patent is
hereby corrected as shown below:

Title page.

Item [75], "Doo-Gyun Kim" should be -- Dae-Gyun Kim --.

Signed and Sealed this

Thirty -first Day of December, 2002

JAMES E. ROGAN

Director of the United States Patera and Trademark Office

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